Pain. Without it, some say there can be no gain. Which probably explains my largely unsuccessful, thoroughly cosseted life - I’m a total wuss.

One thing’s for sure, you’re not going to get anywhere in Knights Onrush without a whole heap of pain. In fact, any time spent with the game - successful or not - is going to be fraught with hurt. As I type this review, my left wrist is locked into a claw-like shape and my right forefinger feels like it’s gone 12 rounds with Vitali Klitschko.

Fortunately, along with that pain comes a whole heap of gain. This is one of the most chaotically fun games to be found on the App Store.

A cross between the sandbox gameplay of Pocket God and a tower defence game like Fieldrunners, the game asks you to defend a castle from waves of angry knights. While you buy and set up defences as in a tower defence game, it’s up to you to roll up your sleeves and get stuck into the enemy hordes directly.

The simplest way to achieve this is to physically pick each enemy up with a finger and fling him into the air. This won’t be enough as the numbers increase, however, which is where your defences come in to play.

From simple cannons to raging dragons, there’s a fine variety of destructive counter-measures. The ways in which these murderous devices are activated are as varied as their effects.

The aforementioned dragon, for example, likes his meat hung up for him, so you have to grab your hapless foes and place them carefully on a large hook. Meanwhile the giant pillar must be repeatedly slammed onto the ground with your finger, pulverising anything below.

As you work your way through Campaign mode, new and tougher enemies are introduced in ever-greater numbers. The trouble is, the game hits a bit of a plateau rather early. The tactics required to succeed are fairly basic - flick your finger like mad, using one of your uber-weapons when things get particularly hectic or when you find your enemy at the gate.

Knights Onrush’s war is one of attrition. It’s the enemy horde versus your finger and both are likely to come out of the experience badly mauled.

The frantic gameplay isn’t helped by the sense that the controls aren’t quite as sensitive enough. Finger swipes frequently don’t register as sharply as you’d expect, leading to an even more frenzied bout of screen scrubbing in an attempt to compensate.

Also, with a full armoury interface at your disposal the screen becomes congested. It can be tough to pick out a specific defensive measure, especially in the heat of battle.

Still, there’s no doubt that Knights Onrush is a classy package, with beautifully drawn and expertly animated sprites. It also possesses a rare sense of knockabout fun that will pull you back time and again for another round.

If it was just a little tighter, a tad more forgiving and a little less painful to play, Knights Onrush would be one of the classic experiences on the App Store. Even given its weaknesses, though, at just 59p it’s well worth the pain.